<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-form label-width="120px">

        <el-form-item label="课程标题">
            <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>

        <!-- 所属分类 TODO -->
         <el-form-item label="课程分类">
            <el-select
                v-model="courseInfo.subjectParentId"
                placeholder="一级分类" @change="subjectLevelOneChanged">
            
                <el-option
                    v-for="subject in subjectOneList"
                    :key="subject.id"
                    :label="subject.title"
                    :value="subject.id"/>

            </el-select>

            <!-- 二级分类 -->
             <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
                <el-option
                    v-for="subject in subjectTwoList"
                    :key="subject.id"
                    :label="subject.title"
                    :value="subject.id"/>
            </el-select>
        </el-form-item>


        <!-- 课程讲师 TODO -->
        <!-- 课程讲师 -->
        <el-form-item label="课程讲师">
        <el-select
            v-model="courseInfo.teacherId"
            placeholder="请选择">

            <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>

        </el-select>
        </el-form-item> 

        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>

        <!-- 课程简介-->
        <el-form-item label="课程简介">
            <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>


        <!-- 课程封面 TODO -->
        <!-- 课程封面-->
        <el-form-item label="课程封面">

            <el-upload
                :show-file-list="true"
                :on-success="handleAvatarSuccess"
                :before-upload="beforeAvatarUpload"
                :action="BASE_API+'/eduoss/fileoss'"
                class="avatar-uploader">
                <img :src="courseInfo.cover">
            </el-upload>

        </el-form-item>

        <el-form-item label="课程价格">
            <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>

        <el-form-item>
            <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存</el-button>
        </el-form-item>
        </el-form>
  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'
export default {
    components: { Tinymce },
    data() {
        return {
            saveBtnDisabled:false,
            courseInfo:{
                title: '',
                subjectId: '',//二级分类id
                subjectParentId:'',//一级分类id
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: '/static/01.jpg',
                price: 0
            },
             BASE_API: process.env.BASE_API, // 接口API地址
             teacherList:[],//封装所有的讲师
             subjectOneList:[],//一级分类
             subjectTwoList:[],//二级分类
             courseId:''//课程ID
             //unique:0
        }   
    },
    created() {
        this.init()
    },
     watch: {  //监听
        $route(to, from) { //路由变化方式，路由发生变化，方法就会执行
            this.init()
        }
    },
    methods:{
        //上传封面成功调用的方法
        handleAvatarSuccess(res, file) {
            this.courseInfo.cover = res.data.url
        },
        //上传之前调用的方法
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2

            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        //点击某个一级分类，触发change，显示对应二级分类
        subjectLevelOneChanged(value) {
            //value就是一级分类id值
            //遍历一级分类
            for(var i=0;i<this.subjectOneList.length;i++){
                //判断点击的value和所有的一级分类哪个ID是一致的
                if( value === this.subjectOneList[i].id){
                    //将该一级分类的children赋值给subjectTwoList
                    this.subjectTwoList = this.subjectOneList[i].children
                    this.courseInfo.subjectId='' //当点击一级分类时，先清空上轮二级分类中值
                }
            }
        },
        //查询所有的一级分类
        getOneSubject() {
            subject.getSubjectList()
                .then(response => {
                    this.subjectOneList = response.data.list
                })
        },
        //查询所有的讲师
        getListTeacher() {
            course.getListTeacher()
                .then(response => {
                    this.teacherList = response.data.items
                })
        },
        addCourse(){    //添加课程并进入下一步
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '添加课程信息成功!'
                    });
                    //回到课程列表
                    this.$router.push({path:'/course/list'})
                })
        },
        updateCourse(){ //修改课程完毕进入下一步
            course.updateCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '修改课程信息成功!'
                    });
                    //回到课程列表
                    this.$router.push({path:'/course/list'})
                })
        },
        //保存课程数据
        saveOrUpdate() {
            //当courseInfo中有ID时就修改，否则添加
            if(this.courseInfo.id){
                this.updateCourse()
            }else {
                this.addCourse()
            }
        },
        //回显数据
        getCourseInfo() {
            course.getCourseInfo(this.courseId)
            .then(response => {
                //获取课程数据
                this.courseInfo = response.data.courseInfoVo

                //得到所有的一级分类
                subject.getSubjectList()
                .then(response => {
                    this.subjectOneList = response.data.list
                    //遍历所有的一级分类和课程信息的一级分类，相同就获取其所有二级的数据
                    for(var i=0;i<this.subjectOneList.length;i++){
                        //得到当前的一级分类
                        var oneSubject = this.subjectOneList[i];

                        //判断一级分类和课程信息的一级分类是否相同
                        if(oneSubject.id === this.courseInfo.subjectParentId){
                            //获取其所有二级的数据
                            this.subjectTwoList = oneSubject.children
                        }
                    }
                })   
            })
        },
        //添加课程初始化
        initSaveCourse(){
            //清空表单的数据
            this.courseInfo={}
            //this.courseInfo.description=''
            
            this.courseInfo.cover='/static/01.jpg'
            this.courseId=''

            //清空二级分类
            this.subjectTwoList=[]
            console.log("课程表单数据清空了")
            //初始化所有讲师
            this.getListTeacher()
            //初始化一级分类
            this.getOneSubject()
        },
        //回显课程初始化
        initUpdateCourse(){
            this.courseId = this.$route.params.id
            //调用根据id查询课程的方法
            this.getCourseInfo()
            //初始化所有讲师
            this.getListTeacher()
        },
        init(){
            //判断是否传入课程ID，有的话回显数据
            //获取路由id值
            if(this.$route.params && this.$route.params.id) {  //修改课程的情况
                this.initUpdateCourse()
            }else{  //添加课程的情况
                this.initSaveCourse()
            }
        }
    }
}
</script>
<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>
